在Java FileWriter和FileReader中，是否可以使用对象？

Question

请考虑这些代码：有可能使用文件编写器和FieleRead与类学生对象吗？

Student s1 = new Student();
s1.input();//I want to write this method in a File
FileWriter out2 = new FileWriter("input.txt");
out2.write();
out2.flush();
out2.close();

s1.display();//I want to Read this method in a File
FileReader in2 = new FileReader("input.txt");
in2.read(); 
in2.close(); 

Answer 1

是的，您可以使用FileOutputStream保存您喜欢的任何对象，并使用FileInputStream获取它（作为对象，您需要在此之后进行强制转换）。试试看。 例如：

    FileOutputStream fos = null;
    ObjectOutputStream writer = null;
    Student data = new Student();
    try{            
        fos = new FileOutputStream(fileName);
        writer = new ObjectOutputStream(fos);

        writer.writeObject(data);
    }
    catch (IOException ex){
        ex.printStackTrace();
    }

请记住关闭它并执行异常练习：-）

因为我发现了一个旧的完整的工作示例类，所以您可能需要对其进行研究（这是非常难看的代码，但它确实起到了作用）：

import java.io.*;

public class Test {

    static boolean checkFile(File file) {
        if (file != null) {
            if(file.isFile()){
                return true;
            }
            try {
                file.createNewFile();
            } catch (IOException e) {
                System.err.println("Error creating " + file.toString());
            }
            if (file.isFile() && file.canWrite() && file.canRead())
                return true;
        }
        return false;
    }

    static boolean writeFile(String dat, Object data){
        FileOutputStream fos = null;
        ObjectOutputStream writer = null;

        try{            
            fos = new FileOutputStream(dat);
            writer = new ObjectOutputStream(fos);

            writer.writeObject(data);
        }
        catch (IOException ex){
            ex.printStackTrace();
            return false;
        }
        finally{
            try{
               if(writer!=null){
                   writer.close();
               }
            }
            catch (IOException ex){
                ex.printStackTrace();
            }

            try{
                if(fos!=null){
                    fos.close();
                }
            }
            catch (IOException ex){
                ex.printStackTrace();
            }
        }   
        return true;
    }

    static Student readFile(String dat){
        FileInputStream fis = null;
        ObjectInputStream reader = null;
        Student student = null;

        try{            
            fis = new FileInputStream(dat);
            reader = new ObjectInputStream(fis);

            student = (Student) reader.readObject();
        }
        catch (Exception ex){
            ex.printStackTrace();
        }
        finally{
            try{
               if(reader!=null){
                   reader.close();
               }
            }
            catch (IOException ex){
                ex.printStackTrace();
            }

            try{
                if(fis!=null){
                    fis.close();
                }
            }
            catch (IOException ex){
                ex.printStackTrace();
            }
        }   
        return student;
    }

    public static void main(String[] args){
        Student student = new Student("Horst");
        String filename = "input.txt";
        boolean worked = false;
        if(checkFile(new File(filename)))
            worked=writeFile(filename, student);
        student = new Student("not Horst");
        if(worked)
            student= (Student) readFile(filename);
        System.out.println("Student : " + student.name);
    }

}

class Student implements Serializable{

    public String name;

    public Student(String name){
        this.name=name;
    }
}